[glib-networking] Upgrade CI to Fedora 29

[Michael Catanzaro <mcatanzaro src gnome org>]

commit be2598039e1c39ffd6c6a4f9649a5dacdba621ed
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Sun Nov 11 19:06:27 2018 -0600

    Upgrade CI to Fedora 29
    
    This should no longer be broken.
    
    And the CI on Fedora 28 actually is broken currently. See the previous
    commit for why it's OK to just upgrade the CI rather than fix that.

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 7c4358e..6fe7d95 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,4 +1,4 @@
-image: fedora:28
+image: fedora:29
 
 variables:
   ADDITIONAL_DEPENDENCIES: gsettings-desktop-schemas gcc libasan